Biological Invasion - Ecology

Ecology topic

1. ECOLOGY AND ECOSYSTEMS Assignment Work B I O L O G I C A L INVASIONS Submitted to : Dr Sandeep Kaushik Department of EVS Submitted by : SHIVAM SONU BSc – EVS ( IIIrd Sem ) 2019-20 INDIRA GANDHI NATIONAL TRIBAL UNIVERSITY, AMARKANATAK

2. CONTENT Definition of Biological Invasion Concept of exotics and invasive species Invasive Species Spread Characteristics of invaders Stage of invasion Mechanism of invasion Invasive pathways Impacts of invasion on ecosystem and communities

3. BIOLOGICAL INVASION

4. INVASIVE SPECIES An invasive species can be any kind of living organism—an amphibian (like the cane toad), plant, insect, fish, fungus, bacteria, or even an organism’s seeds or eggs—that is not native to an ecosystem and causes harm. They can harm the environment, the economy, or even human health. Species that grow and reproduce quickly, and spread aggressively, with potential to cause harm, are given the label “invasive.”

5. Invasive species are among the leading threats to native wildlife. Approximately 42 percent of threatened or  endangered species  are at risk due to invasive species. Human health and economies are also at risk from invasive species. The impacts of invasive species on our natural ecosystems and economy cost billions of dollars each year. Many of our commercial, agricultural, and recreational activities depend on healthy native ecosystems. An invasive species does not have to come from another country. For example, lake trout are native to the  Great Lakes , but are considered to be an invasive species in Yellowstone Lake in Wyoming because they compete with native cutthroat trout for habitat.

6. Concept of exotics species Exotic = Foreign Or Also called as Alien species. Defination : Invasive alien species (IAS) are species whose introduction and/or spread outside their natural past or present distribution threatens biological diversity. IAS occur in all taxonomic groups, including animals, plants, fungi and microorganisms, and can affect all types of ecosystems. While a small percentage of organisms transported to new environments become invasive, the negative impacts can be extensive and over time, these additions become substantial.

7. Examples of Invasive Species Cogon Grass  is an Asian plant that arrived in the United States as seeds in packing material. It is now spreading through the Southeast, displacing native plants. It provides no food value for native wildlife, and increases the threat of wildfire as it burns hotter and faster than native grasses.

8. Feral pigs  will eat almost anything, including native birds. They compete with native wildlife for food sources such as acorns. Feral pigs spread diseases, such as brucellosis, to people and livestock.  E. coli  from their feces was implicated in the  E. coli  contamination of baby spinach in 2006.

9. European green crabs  found their way into the San Francisco Bay area in 1989. They outcompete native species for food and habitat and eat huge quantities of native shellfish, threatening commercial fisheries.

10. Water hyacinth  is a beautiful aquatic plant, introduced to the U.S. from South America as an ornamental. In the wild, it forms dense mats, reducing sunlight for submerged plants and aquatic organisms, crowding out native aquatic plants, and clogging waterways and intake pipes.

11. Characteristics of invaders The characteristics of invading species were explored using the Ecological Flora Database, and by using comparisons available in other studies. Invasion success has been related to both abundance and distribution in the native range, which are themselves related. Abundance is probably the key variable. In the British flora invading species are characterized more by their distribution and morphology than by their life history and reproductive behaviour . The size of the plant and characters related to propagule pressure created by humans come out as important correlates of success. For biological characters, genetic studies and the phenomenon of boom-and-bust both suggest that the critical interaction between species and habitat is often subtle. Nevertheless, studies on pines and squirrels show that such important biological characters can be determined.

12. Stage of invasion An invasive species is defined as a non-native species to an ecosystem whose introduction causes economical, medical, and/or environmental harm. Invasive species can include plants, animals, and microbes.  1. The first of stage of invasion , introduction involves the movement of a species into a non-native area; human transport is the most dominate form of invasive species introduction. Humans have the capability to move species to places that would be otherwise inaccessible for species. People may introduce a species intentionally or accidentally. An intentional pathway can only be judged by the impacts of the organism. Some accidentalpathways include ballast water discharge, importation of resources, and the immigration of people. However, species may invade through natural pathways like wind and water currents. 2. The second stage of invasion , colonization is the initial interaction between the invasive species and the habitat. Whether or not the species survives is up to the species persistence and chance. Sometimes, successful colonization involves repeated introductions to overcome natural and human boundaries

13. 3. The third stage of invasion , establishment means the species successfully colonized into the environment and is able to reproduce. The first three stages usually requires human intervention but after the species disperses into the environment the species no longer needs assistance. 4. The fourth stages of invasion is the dispersal of the new species and formation of populations across the environment. The United States Department of Agriculture offers detailed information on invasive species at the National Invasive Species Information 

14. Mechanism of invasion The mechanisms of invasion of a parasite into host tissue or host cells. Single cell protozoan parasites evade the host immune response by residing within host cells and enter the host cell with minimal trauma to ensure that they preserve an environment suitable for their replication and do not trigger a lethal host immune response. This intracellular invasion paradigm is also shared by a helminth parasite,  Trichinella spiralis . Often an invasive larval form penetrates skin or the mucosa of the gastrointestinal tract to enter into the host.. The chapter states that the invasion phenomenon itself can be divided into three successive steps: recognition and attachment, internalization and vacuole development, vacuole maturation.  Entamoeba histolytica ,  which is a protozoan, does not invade intra cellularly at any stage of its life cycle unlike other protozoas . The process of its invasion ( extracellularly ) and its properties are also elaborated in the chapter. .To complete the invasion process, helminth parasites have evolved sensory organs for finding and navigating within the host, attachment mechanisms utilizing specialized mouth structures or glue-like secretions, and hydrolytic enzymes to digest macromolecular barriers in the extracellular space

15. Invasive pathways Pathways  are the means and routes by which invasive species are introduced into new environments. Pathways can generally be classified as either  natural  or  man-made . Natural  pathways (i.e., those not aided by humans) include wind, currents (including marine debris), and other forms of natural dispersal that can bring species to a new habitat. Man-made  (or human-mediated) pathways are those which are created or enhanced by human activity. These are characteristically of two types: a). Intentional b). Unintentional

16. Intentional , which is the result of a deliberate movement of a species by humans outside of its natural range. Examples include the introduction of biological control organisms or the movement of species for the horticultural or pet trade. Intentional introductions as a whole should not be labeled as either good or bad. A specific intentional pathway can only be judged by the positive or negative impact of the specific organisms that are moving along that means.   Unintentional,  which is the inadvertent movement of species as a byproduct of some other human activity. Examples of unintentional pathways are  ballast water  discharge (e.g. red-tide organisms), pests and diseases in imported plants,  firewood , and other agricultural products (e.g.  fire ants ), the movement of recreational watercraft (e.g.  zebra mussels ), and the international movement of people (e.g. pathogens). In these and countless other unintentional pathways, the movement of non-native species is an indirect byproduct of human activities.

17. Examples of ways invasive species spread include: Agricultural materials Aquaculture farming Ballast water and shipping Classroom or science lab (escapes or introductions) Firewood Fishing gear Food trade and its packing material Fouled hulls of commercial and recreational vessels Internet sales Moving Outdoor gear (hitchhikers on boots, clothes, and camping equipment) Passenger baggage Pets (unwanted or escaped) Plants and plant parts (escaped or disposals) Recreational boats Recreational vehicles (RVs)

18. Impacts of invasion on ecosystem and communities

19. 10

20. THANK YOU